Riviera was a great idea on paper, but in practice it divided the game into two completely separate play styles. You either knew what you were doing and constantly walked over the game, or you didn't and got your ass constantly handed to you.
Still, nobody else has really tried what it did since, so there's that going for it.
Belated but:
You remembered correctly in that Feena is very forward and a strong character in the ghost ship, but I can't stand Grandia's ghost ship in general. It was actually one of the ships I was thinking of when I made that comment. The problem with ghost ships is that they're almost always filler, and I can only think of a handful of plot related ones. Legend of Dragoon comes to mind, being very important in the grand scheme of the plot, but you don't realize it until later. It still falls under my banner of ghost ships being annoying because both the encounters and the boss are horrible.
I suppose I do like Breath of Fire 3's, but it's not a ghost ship in a traditional sense.
As for the damsel in distress bit, I wouldn't say Feena is a damsel in distress throughout the entire game, simply that her outspoken attitude from the ghost ship is downplayed more as the story progresses. She's never quite "weak" or "helpless," but there are a few times where she needs rescuing.
Maybe. But I cant help but see it as her personality getting more and more subdued as time went on to make way for Justin becoming more and more of a man until the end where she hit full on damsel in distress for Justin to save along with the world and the day and to graduate into a full fledged hero (at that point Feena is little more than his diploma).
It kinda leads me to my beef with the Grandia series on the whole. None of the games have a decent cast. Its basically the main hero, the chick who turns out to be a walking plot macguffin magical girl, the buddy, the twerp, the older guy/sudo mentor, the android chick found in some ruins, and maybe another chick who's both the least dislikable and only shows up for a dungeon or two then gets ditched/bails. Also the settings file themselves right into the same bad writing category as FFVIII's setting (i.e. they disintegrate into a goofy ball of cobbled together analogues, metaphors, cliches, and elemental based gimmick dungeons, the very moment Mr. Scrutiny violates his restraining order to stay at least 50ft away from the writing).